So far, in this house I've found: CPCs wrapped under the heads of wood screws securing a plastic pattress box, dishwasher wired brown-to-black and blue-to-red, shelving supports fixed with 1/2" screws (barely in the plaster), door hinges secured with long BZP pozi screws that have the plain shank in the door frame, BZP posi screws everywhere, a kitchen extractor blowing into a capped chimney, a concealed shower mixer fitted without thought of how to service it (there's a leak!), a 13A socket connected to a ceiling rose, T&E run on catenary wires to sheds (signed off a year ago but the insulation had degraded so far it was falling off). Today I found that the spur to a double 13A socket runs in a rough channel in the concrete underneath a parquet floor. Sigh! I haven't checked yet but it's probably a spur from a spur. Fortunately there haven't been any structural "improvements". Please people, if you don't know what you're doing then don't do it!
I feel much better for that vent. I'm ready for my medicine now nurse ;-)